Various medical procedures, particularly cardiology procedures, involve accessing a corporeal vessel through a percutaneous sheath. The sheath necessarily requires the formation of a hole or opening in the vessel wall so that a medical procedure can be performed via the sheath. After the particular medical procedure has been performed, the sheath must eventually be removed from the vessel and the access hole in the vessel wall must be closed.
A number of prior vascular closure devices have been developed in attempting to provide a solution for the problem of closing a hole in the vessel wall. Tissue approximation typically involves passing a length of suture into and through adjacent vessel and subcutaneous tissue, across the vessel opening, and back into and through adjacent vessel and subcutaneous tissue. Certain prior closure devices have involved relatively complicated methods and devices for extracting a length of suture from inside the vessel so that the physician can approximate tissue surrounding the hole in the vessel wall through use of the suture.
After the suture has been placed across a hole in the vessel and the treatment of the patient through the hole is completed, the suture may be used to seal the hole. Various devices such as suture locking devices, suture knot placement devices, and suture cutting devices may be used as part of a procedure to seal the hole using the suture. These devices are delivered to the hole by access through a layer of subcutaneous tissue, the thickness of which may vary between patients. Proper sealing of the hole using the suture is often dependent on accurate positioning of these devices within the subcutaneous tissue.